Motor vehicle lift



May 29, 1934. W F, ESSEX 1,960,871

MOTOR VEHICLE LIFT Filed March 3. 1934 INVENTOR l/l/IZzaz FEex ATTORNEYPatented May 29, 1934 MOTOR yVEHICLE LIFT William F. Essex, Chicago,Ill., assigner to Standard @il Company, Chicago, nl., a corporation ofindiana Application March e, i534, serial No. naves 10 Claims.

This invention relates to improvements in motor vehicle lifts and moreparticularly to im- ]lpigfements in super structure for motor vehicle Inthe past, motor vehicle lifts of the type used in automotive lubricationservice stations wherein the 'motor vehicle is elevated thereby duringthe lubricant servicing operation have been constructed with runwayslying in a rlat l0' horizontal plane upon which the vehicle may bedriven and so remain during the time that the lift is in an elevatedposition. Vehicle lifts of this type require some type of chock forpreventing the vehicle from rolling along the runi ways, such forinstance as cross bars placed across the runway at the outer ends of thewheels after the vehicle has been moved into position upon the lift. Thepositioning of the vehicle upon the runway in the conventional type ofmotor vehicle lift is left to the discretion of the operator or to theperson who drives the vehicle thereupon and although it is mostadvisable and advantageous that the center of gravity of the vehicle belocated directly over the elevating plunger of the lift, the dispositionof the center ofrgravity, or center of mass, of the vehicle over theplunger may only be determined and brought about, if such procedure ispracticed at all, by sheer guess work on the part of the operator.

If the center of gravity of the vehicle is located forwardly orrearwardly of the axis of the lift plunger with respect to the runways,unnecessary friction is developed between the plunger and the packingfor the cylinder within which the plunger is operatively mounted. Thisfriction necessitates the expenditure of additional power to elevate theloaded lift. In addition to such waste of power, the unbalanced loadupon the lift represented by the disposition of the center of gravity ofthe vehicle forwardly or rearwardly of the plunger axis may result inmutilation of the cylinder plunger packing, and, in such instances asWhere the liftis of the rotary type,

serious scoring to the side walls of the plunger may result due to thetendency of the plunger to cant with respect to the cylinder, thereuponcompressing the packing material and engaging with the packing bushingsand adjacent cylinder structure.

An object of my invention is to provide an improved motor vehicle liftwherein the motor vehicle is automatically located upon the run- 'waysto iocate the center of gravity or mass of the vehicle directly over theplunger of the lift thereby to balance the load thereupon.

(El. 25d-39) A further object is to provide' a motor vehicle lift, asdescribed, wherein the motor vehicle when driven upon the runwaysthereof adjusts itself thereupon to balance the load thus placed uponthe lift with respect to the opposed portions oi the runways on eitherside of the plunger regardless of whether the center of gravity of thevehicle is located centrally of the wheel base of the vehicle or isforwardly or rearwardly of the center of the wheel base.

A further object is to provide a motor vehicle lift of the characterdescribed which requires a minimum amount of power in elevating theloading lift for a given load.

Other objects, the advantages, and uses of the invention will becomeapparent after reading the following specification and appended claimsand after consideration of the drawing forming a part of thespeciiication wherein:

Fig. 1 is a side elevation of a motor vehicle lift incorporatingfeatures of my invention;

Fig. 2 is a sectional view along the line ELI- H of Fig. l;

Fig. 3 is a sectional view along the line III-III of Fig. l; and

Figs. fl, 5, 6 and 7 are schematic views illustrative of modiiied formsof `'the runways for the lift.

With reference to Fig. 1, I `have illustrated therein a motor vehiclelift having a hydraulic 4cylinder 1, which may be embedded in the floorof the service station or other enclosure wherein the lift is to beemployed, a plunger 2 mounted for movement along the vertical axiswithin the cylinder l, suitable packing 3 and packing gland 4 beingprovided to maintain a fluid seal between the cylinder and the plunger.A box type cross l member 5 may be securedto the upper end of theplunger 2 to serve as a support for the parallel runways 6.` The runways6 are spaced at a suiiicient distance from one another, and are of suchwidth, as to receive the wheels 7 of a motor vehicle thereupon, one ofwhich is indicated at 8 in Fig. 1. Flanges 9 may be formed on theadjacent or inner edges of the runways to guide the 100 Vehicle on therunway and to prevent lateral displacement of the vehicle thereupon.Ramps l0 may be hingedly mounted at each end of each runway to assist inthe driving of the vehicle upon the runway when the plunger 2 is at the105 lower limit of its travel.

In the form of superstructure, i. e., runways 6, illustrated in Fig. l,it will be noted that the central portion of the runways from the dottedcross line 11 to the cross line 12 are :dat and lie 110 in a horizontalplane and that the end portions of the runways from points 11 and 12 tothe outer ends thereof curve upwardly. The rise of the curved portionthereof above the plane of the central portion of the runways, exclusiveof the ramps 10 may be about four inches. In the embodiment'shown inFig. 1, the curved sloping end portions of the runways are preferablycircular arcs which are tangent tothe fiat portions 11-12 of therunways.

This formation of the runways, which for the purpose of illustration hasbeen somewhat exaggerated throughout the drawing, provides for theresting of the wheels 7 of the vehicles driven upon the lift upon thesloping portions of the runways. Therefore a vehicle having its centerof 1 gravity or mass forwardly of the central portion of the wheel baseas represented by the vehicle shown at 8 in Fig. 1 will come to restupon the runways when permitted to move thereupon,

without 'the retention of the Wheel brakes, to av position asillustrated with its center of gravity or mass over the plunger 2. Suchdisposition of the vehicle, as will be noted, results in the rearwardend of the vehicle rising upwardly upon the sloping lift end of therunways whereas the f will depend entirely upon the location of thecenter of gravity without regard to the physical dimensions of thevehicle. Inasmuch as this functioning of the lift to so locate thevehicle is entirely automatic the operator need only to wait until thevehicle comes to a standstill upon the runways whereafter he may, if heso desires, place suitable chocks upon the runways to precludeaccidental shifting of the vehicle as during the servicing operation,although it will be quite apparent that the tendency of the vehicle toshift 1ongitudinally upon the runways will beV resisted to a markeddegree dueto the fact that in order to So shift ineither direction thecenter of gravity of the vehicle must be elevated. y

In Fig. 4 I have illustrated anpther form of the runway structurewherein the runways are of uniform curvature throughout as indicated at6a,

the curvature thereof being developed about centers lying in a planeincluding' the axis of the plunger2. I prefer to employ a radius of suchlength as to locate the remote ends of the run ways ata distance notmore than 4" above the lowest or midpoint of the runways.

` drawing, I have exaggerated the curvature of the runways for thepurpose of illustration.

The runway construction illustrated in Fig. 5 is lift cylinder 1 isembedded thereby to facilitate the movement of the vehicle to and fromthe runways.

In this, figure, as well as the remaining figures of the of the plunger2.

In Fig. 6 I have illustrated a further modification of the runwaystructure wherein the runways 6b are curved, the form of the curve beingsuch that the radius of curvature continually decreases from a maximumat the center of the runway to a minimum at the outer ends. Such a formof curve may be developed by well known mathematical methods. Among thetypes of mathematically devised curves which might be utilized are theellipse, parabola, hyperbola, cycloid, trocloid and various spirals.

I have illustratedv in Fig. 'I a further modication of the runwaystructure wherein as in the case of the structure of Fig. v6, the outerends thereof except` that as in the case of the runways of Fig. -5, themid-portion 14 of the runways for a distance less than the wheel base ofthe vehicle to be supported are nat and lie in a horizontal plane.

While I have described a preferred example of myinvention it should beunderstood that I do not limit myself to the details hereinabove setforth except as dened by the following claims.

` I claim:

1. A motor vehicle lift comprising, a movable lift plunger, and a motorvehicle runway supported upon said plunger, said runway lying in asubstantially horizontal plane and having those portions thereof uponwhich the wheels of a vehicle rest when upon said runway slopingupwardly from the mid-portion of the runway at 115 a constantlyincreasing angle.

2. A motor vehicle lift comprising, a vertically movable lift plunger,and a motor vehicle runway supported at its mid-point upon said plunger,said runway having those portions upon which the wheels of a vehicle mayrest .when upon the runway curved upwardly in the direction of the endsof the runway, the curvature of each of said portions being the same.

3. A motor vehicle lift, comprising a vertically movable' lift plunger,and a motor vehicle runway supported at its mid-point upon saidplunger,vsaid runway lying in a substantially horizontal plane andsloping upwardly at its opposite end portions at a constantly increasingangle toward the adjacent ends of the runway.

4. A motor; vehicle lift as defined in claim 2` wherein the radius ofcurvature of said runway portions is constant l 5. A motor vehicle 11aas defined in claim 2 135 wherein the said runway portions are in theform of circular arcs having a common center.

6. A motor vehicle lift as dened in claim 2 wherein the curvature ofsaid nmway portions is variable and developed from` a common point.

7. A motorvehicle lift as deflned in claim 2 wherein the radius ofcurvature of "said runway portions gradually decreases in the directionof the remote ends of the runway.

8. In a motor vehicle lift, -a runway supported at its mid-point, saidrunway being curved to present an upwardly facing surface of concavecurvature upon which the wheels of a motor ve- .hicle may rest thereby`to locate the center of 15G v gravity of the vehicle over the mid-paintof the lill of a vehicle to be supported theleupon wool mw ing its endportions sloping upwomlly www imm ,the smid l'loxlomml portion al; a,comstafnlly nw. lm o motor vehicle llill., a moto? vehicle runway :osdellneol lm clolm 9 Wlmein the remote :ends ol the runway me locale-clmoi', more than fom inches abovsaid lwlzontall portion.

' 1w., ESSEX.

